Performance of semiconductor devices may often be increased by epitaxially growing other materials, such as group III-V materials, on a semiconductor substrate. The difference in the lattice structure between the epitaxial material and the semiconductor substrate causes a stress in the epitaxial layer. This stress in the epitaxial layer may improve the speed and performance of integrated circuits. For example, to further enhance transistor performance, transistors have been fabricated using strained channel regions located in portions of a semiconductor substrate. Strained channel regions allow enhanced carrier mobility to be realized, thereby resulting in increased performance when used for n-channel or for p-channel devices. Generally, it is desirable to induce a tensile strain in the channel region of an n-channel transistor in the source-to-drain direction to increase electron mobility and to induce a compressive strain in the channel region of a p-channel transistor in the source-to-drain direction to increase hole mobility.
During the epitaxial growth process, however, dislocations form in the interface between the epitaxial layer and the semiconductor material due to the difference in the lattice structures of the different materials. These dislocations extend from the interface through the epitaxial layer. In some instances, the dislocations may extend to a surface of the epitaxial layer. In situations such as these in which the dislocations extend to or near the surface, the dislocations may adversely affect the performance of the devices formed therein.